I prefer pen drives (also called flash drive and jump drive)...small harddrives that plug into a USB port. They range from a few megabytes to a couple of gigabytes...and $100 to $800 in price. Datace has a 4 gig flashdrive for $170.
I use
Replicator. It's freeware and works as advertised. Set it up once and configure it to run on a schedule you choose. It's never failed to do its job for me.
It says it will back up directly to CD but I haven't tried that feature. Others who have say its backing up to CD is hit or miss at best. I set it to back up to a folder on the harddrive and then burn that folder to CD.